Q1: What are rocks?
Ans: Rocks are the combinations of homogenous substances called minerals.
Q2: What is the role of a geologist in studying about a mineral?
Ans: A geologist is interested in the formation of minerals, their age and physical and chemical composition.
Q3: What is an ‘ore’?
Ans: The term ‘ore’ is used to describe an accumulation of any mineral mixed with other elements. The mineral content of the ore must be in sufficient concentration to make its extraction commercially viable.
Q4: What are ‘veins’ and ‘lodes’?
Ans: In igneous and metamorphic rocks, minerals may occur in the cracks, crevices, faults or joints. The smaller occurrences are called veins and the larger are called lodes.
Q5: How are minerals formed in veins and lodes?
Ans: In most cases, they are formed when minerals in liquid molten and gaseous forms are forced upwards, through cavities towards the earth’s surface. They cool and solidify as they rise.
Q6: Name the minerals obtained from veins and lodes.
Ans: Major metallic minerals like tin, copper, zinc and lead, etc. are obtained from veins and lodes.
Q7: In what form do minerals occur in sedimentary rocks?
Ans: In sedimentary rocks, minerals occur in the form of ‘beds’ and ‘layers’.
Q8: How are minerals formed in sedimentary rocks?
Ans: They are formed as a result of deposition, accumulation and concentration in horizontal states.
Q9: Name the minerals formed in beds and layers.
Ans: Sedimentary minerals include iron ore, coal, gypsum, potash salt and sodium salt.
Q10: What are ‘placer deposits’?
Ans: When minerals occur as alluvial deposits in sands of valley floors and the base of hills, then deposits are called ‘placer deposits’.
Q11: Name minerals formed as ‘placer deposits’.
Ans: Gold, silver, tin and platinum are the most important ones among minerals formed as ‘placer deposits’.
Q12: Which minerals are derived from oceanic waters?
Ans: Common salt, magnesium and bromine are largely derived from ocean waters.
Q13: Which factors affect the economic viability of a reserve?
Ans: The concentration of minerals in the ore, the ease of extraction and closeness to the market play an important role in affecting the economic viability of a reserve.
Q14: What are ferrous minerals?
Ans: Minerals which contain iron-content in it are called ferrous minerals.
Q15: What is Magnetite?
Ans: Magnetite is the finest iron ore with a very high content of iron upto 70 per cent. It has excellent magnetic qualities, especially valuable in the electrical industry.
Q16: What is Haematite?
Ans: Haematite ore is the most important industrial iron ore in terms of the quantity used, but has a slightly lower iron content than magnetite, i.e., 50-60 per cent.
Q17: Name the two types of iron-ore found in India.
Ans: Magnetite and Haematite.
Q18: In which places of Odisha-Jharkhand belt is iron ore found?
Ans: High grade Hematite iron ore is found in Badampahar mines in Mayurbhanj and Kendujhar district and in Singhbhum District of Jharkhand, iron-ore is mined in Gua and Noamundi.
Q19: Where are Bailadila hills located and why are they called so?
Ans: Bailadila hills are located in the Bastar District of Chattisgarh. These Bailadila hills look like the ‘hump of an ox’, hence they are called so.
Q20: Name the countries to which iron-ore is exported from Bailadila hills.
Ans: Iron-ore from these mines is exported to Japan and South Korea via Vishakhapatnam port.